Jeremy Sher is a member of the Hampstead & Kilburn Conservative Association.

The Supreme Court’s decision in the Brexit case confirmed that the UK Government must seek Westminster’s approval in order to trigger the process of withdrawal from the EU. The Court’s decision also highlights (again) the need for a new referendum procedure.

Until 1975, referendums had no place in the UK’s system. In 1975 and 2016, referendums were used to seek popular consent to implement major constitutional changes. In both cases, a vote requiring only a simple, popular majority was considered all that was necessary to pass the question. However, this model does not incorporate representative or regional legitimacy. These are also essential features of the modern constitutional system in the UK and other democracies around the world. Their omission from the process has created much of the constitutional and political disarray that we are now witnessing.

The Brexit case raises two immediate constitutional problems.

First, if Parliament must pass an Act approving the withdrawal from the EU, our representatives are in a difficult position. MPs are apparently overwhelmingly in favour of the UK remaining while the majority of the public voted in favour of Brexit. There is a tension between the representative and popular will that is probably only resolved using political solutions, such as a new election or effective whipping. The position of the unelected Lords, seeking to obstruct, change or even stop Brexit after a popular vote – and presumably after the Commons has authorised the triggering of Article 50 – is even more troubling.

Second, and perhaps more importantly, the biggest constitutional problem created by the Supreme Court’s decision is that it threatens the stability of the Union. On one hand, Westminster has given wide powers to Scotland, Wales and Northern Ireland. On the other hand, Westminster has always retained the power to legislate for Scotland, Wales and Northern Ireland, even where powers have been devolved to the local assemblies. The so-called Sewel Convention states that Westminster will not normally legislate on devolved matters, except where it has consulted with the devolved institutions. The Scottish and Northern Irish governments relied on this convention to argue that they should have a veto over the UK’s decision to withdraw from the EU.

The Supreme Court has now said that the Sewel Convention is not legally-binding; it is a political convention. According to the court, “UK ministers are not legally compelled to consult the devolved legislatures before triggering Article 50. The devolution statutes were enacted on the assumption that the UK would be a member of the EU, but they do not require it. Relations with the EU are a matter for the UK government.”

It is now clear that the devolved assemblies have limited means of vetoing any changes to the UK’s Constitution where Westminster is determined to make them.

These constitutional problems were entirely foreseeable. Indeed, comparable democracies such as the US, Canada and Australia foresaw similar issues of balancing popular, representative and regional will long ago. These problems could have been managed if the UK had incorporated a referendum procedure that reflected its current constitutional arrangements, not those of 1975 and before. Such a procedure should have reflected the fact that popular, representative and regional legitimacy is now essential for constitutional change in the UK of 2016.

America’s constitution takes a careful route to doing so. The US requires that two thirds of both houses of Congress approve a proposal to amend the constitution and that two thirds of state legislatures must also approve any proposals. The Swiss constitution of 1848 evolved this model. Switzerland’s model requires that there is a nationwide majority and a majority of Switzerland’s cantons. Both procedures were the inspiration for the Australian procedure. The UK’s sunburned cousins concluded that representative, popular and regional consent for change was essential. The Australian system operates as follows:

(i) First, the proposal to amend the constitution must have approval of both Houses of Parliament by an absolute majority. Where Parliament disagrees with the Executive, there is a three month period to resolve the deadlock. If there is no resolution, then the Executive is entitled to call a referendum. This gives “representative legitimacy” to any proposals.

(ii) Next, the question is put to the people i.e. the “popular legitimacy” for any proposals.

(iii) Finally, “regional legitimacy” is required. A changes only passes where there is a majority of electors that approve of the change in a majority of states and a majority of all electors across the whole of Australia approve of the change.

This procedure recognises that nations change but that in devolved countries, different regions might have different views on constitutional matters. In order to preserve national unity, there is a means for historically “minority” regions (such as the American South, the smaller states of Australia and Quebec) to halt or object to proposed constitutional changes of the “majority” regions (the American North, the “British” parts of Canada and New South Wales). This structure helps to preserves the integrity and legitimacy of the likes of the US, Canada and Australia.

In the UK, any future referendum leading to constitutional change should require popular, representative and regional consent to avoid the tensions that we are now observing. The popular majority should consent in at least three of the realms that constitute the UK, and there should also be a popular total majority across the whole of the UK. This approach ensures that England cannot be overruled by Scotland, Wales and Northern Ireland. But, the English majority is balanced by the fact that the smaller regions have a means of objecting to change. This gives every part of the Union a voice in how the UK is governed.

This structure does make it more difficult to change the constitution. Yet, given the impact of constitutional change on a nation as a whole, perhaps it is correct that it is not too easy to amend a country’s constitution – the sheer scale and importance of the decision should warrant a robust consensus, to ensure that any and all changes have legitimacy at the popular, representative and regional levels.

I suspect that if we had taken this approach, the Brexit case would have taken on far less importance.